mm/zswap: add the flag can_sleep_mapped
Patch series "Fix the compatibility of zsmalloc and zswap".
Patch #1 adds a flag to zpool, then zswap used to determine if zpool
drivers such as zbud/z3fold/zsmalloc will enter an atomic context after
mapping.
The difference between zbud/z3fold and zsmalloc is that zsmalloc requires
an atomic context that since its map function holds a preempt-disabled,
but zbud/z3fold don't require an atomic context. So patch #2 sets flag
sleep_mapped to true indicating that zbud/z3fold can sleep after mapping.
zsmalloc didn't support sleep after mapping, so don't set that flag to
true.
This patch (of 2):
Add a flag to zpool, named is "can_sleep_mapped", and have it set true for
zbud/z3fold, not set this flag for zsmalloc, so its default value is
false. Then zswap could go the current path if the flag is true; and if
it's false, copy data from src to a temporary buffer, then unmap the
handle, take the mutex, process the buffer instead of src to avoid
sleeping function called from atomic context.
[[email protected]: add return value in zswap_frontswap_load]
Link: https://lkml.kernel.org/r/[email protected]
[[email protected]: fix potential memory leak]
Link: https://lkml.kernel.org/r/[email protected]
[[email protected]: fix potential uninitialized pointer read on tmp]
Link: https://lkml.kernel.org/r/[email protected]
[[email protected]: fix variable 'entry' is uninitialized when used]
Link: https://lkml.kernel.org/r/[email protected]: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Tian Tao <[email protected]>
Signed-off-by: Nathan Chancellor <[email protected]>
Signed-off-by: Colin Ian King <[email protected]>
Reviewed-by: Vitaly Wool <[email protected]>
Acked-by: Sebastian Andrzej Siewior <[email protected]>
Reported-by: Mike Galbraith <[email protected]>
Cc: Barry Song <[email protected]>
Cc: Dan Streetman <[email protected]>
Cc: Seth Jennings <[email protected]>
Cc: Dan Carpenter <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/mm/zpool.c b/mm/zpool.c
index 3744a2d..5ed7120 100644
--- a/mm/zpool.c
+++ b/mm/zpool.c
@@ -23,6 +23,7 @@ struct zpool {
void *pool;
const struct zpool_ops *ops;
bool evictable;
+ bool can_sleep_mapped;
struct list_head list;
};
@@ -183,6 +184,7 @@ struct zpool *zpool_create_pool(const char *type, const char *name, gfp_t gfp,
zpool->pool = driver->create(name, gfp, ops, zpool);
zpool->ops = ops;
zpool->evictable = driver->shrink && ops && ops->evict;
+ zpool->can_sleep_mapped = driver->sleep_mapped;
if (!zpool->pool) {
pr_err("couldn't create %s pool\n", type);
@@ -393,6 +395,17 @@ bool zpool_evictable(struct zpool *zpool)
return zpool->evictable;
}
+/**
+ * zpool_can_sleep_mapped - Test if zpool can sleep when do mapped.
+ * @zpool: The zpool to test
+ *
+ * Returns: true if zpool can sleep; false otherwise.
+ */
+bool zpool_can_sleep_mapped(struct zpool *zpool)
+{
+ return zpool->can_sleep_mapped;
+}
+
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Dan Streetman <[email protected]>");
MODULE_DESCRIPTION("Common API for compressed memory storage");
